GJXDM versions are numbered by three integers X, Y, and Z delimited by periods (X.Y.Z).
Each integer represents a particular class of change:
A version number should NOT be confused with decimal numbers. X, Y, and Z are integers, not digits, and may become greater than 9. For example, 4.89.113 is a legitimate release number (though not likely to ever be used).
GJXDM version 3.0 is the first operational release. Version 3.0 instances will be forward compatible with and validate using the version 3.0.2 schema or appropriate 3.0.2 schema subsets. See the question on compatibility for more details. Prereleases used four numbers to designate versions. There were only four prereleases: 18.104.22.168, 22.214.171.124, 126.96.36.199, and 188.8.131.52. Except for 184.108.40.206, prereleases are still available, but are no longer maintained or supported.